import math, sequtils, strutils

let
  nk = stdin.readLine.split.map parseInt
  n = nk[0]
  k = nk[1]
  a = stdin.readLine.split.map parseInt
  sum = sum a
var
  x = 0
  y = 1

for i in 1 .. n:
  x += (a[n - i] * y) mod sum
  y = y * (k mod sum) mod sum

echo x mod sum